A recent study published in Science Advances, suggests that “envious” is the most common personality type. A computer algorithm classified people based on their behavior in hundreds of social dilemma scenarios and found the majority could be categorized into four basic personality types: optimistic, pessimistic, trustful and envious. Thirty percent of the people were rated as envious.

“These subjects seem to behave as driven by envy, status-seeking consideration, or lack of trust,” the researchers wrote in their paper. “These players prevent their counterparts from receiving more payoff than themselves even when, by doing so, they diminish their own potential payoff.”

Each of the other three personality types ― pessimistic, optimistic and trustful ― described about 20 percent of people. The last 10 percent behaved so erratically that the computer program failed to categorize them. The four new categories, in contrast, describe the types of behaviors that people show in a social context, where they have to interact with others.

The new study analyzed the responses of more than 500 volunteers to hundreds of hypothetical dilemmas in which people could either cooperate with their teammate or act in their own self-interest. But as these new findings show, it’s not just rationality or cooperative spirit that determines what humans end up doing. Their own personalities, too, play a part.

“The results go against certain theories; the one which states that humans act purely rationally for example,” study co-author Yamir Moreno of the University of Zaragoza in Spain said in a press release.

The envious 30 percent failed to cooperate just because they couldn’t stand the thought of potentially being left with a lower payoff than their teammate received. “This points to the difficulty of making people understand when they face a nondilemmatic, win-win situation,” the researchers wrote.

Although the games in the study offer hypothetical scenarios, they resemble many real-life interactions. Imagine that you are partnered with a co-worker on a special project. To achieve spectacular results, you both need to work hard. But it’s not guaranteed that the two of you will be given equal credit for the success of the project. So you might choose to do just the minimum, which certainly prevents your partner from getting unearned praise, but also deprives you of the credit that could come with the best results.